Computer printers commonly employ a single print head positioned on a reciprocating print head carriage. The single print head is moved across the entire recording medium during the printing process. For example, dot matrix printers employ a single print head with a plurality of individual printing elements arranged in an array extending across a rectilinear path of the print head relative to a recording medium. During the printing process, different combinations of these printing elements are activated as the print head is moved across the recording medium to produce desired alphanumeric characters, or the like, on the recording medium.
Printers may, however, employ multiple print heads which move in a coordinated manner across the recording medium. For discussion purposes, a multi-head dot matrix printer 10 is shown in FIG. 1. The multi-head dot matrix printer 10 has three print heads 12a, 12b, and 12c positioned at preset distances on a reciprocating print head carriage. The printing elements contained in the print heads 12a, 12b, and 12c face a platen 14. When the recording medium, such as paper, is loaded into the dot matrix printer 10, the paper travels between the print heads 12a, 12b, and 12c and the platen 14. The print heads 12a, 12b, and 12c traverse the paper in a reciprocating pattern in a direction perpendicular to the direction of travel of the paper.
A conventional ribbon cartridge for use in a printer having multiple print heads is shown in both FIGS. 1 and 2. The conventional printer ribbon cartridge 16 has a cartridge housing 20 which houses and protects a continuous print ribbon 18. The cartridge housing 20 includes a housing body 21 and two guide arms 22 and 24. The housing body 21 stores the bulk of the print ribbon 18. The two guide arms 22 and 24 extend substantially perpendicular from the housing body 21 to support and guide the print ribbon 18 from the housing body 21 and around the printing elements of the print heads 12a, 12b, and 12c. The printer ribbon cartridge 16 also has multiple ribbon guides 26a, 26b, and 26c, which guide the print ribbon 18 between the respective printing elements of print heads 12a, 12b, and 12c and the platen 14. The ribbon guides 26a, 26b, and 26c are slidably mounted to the print ribbon 18 so that the ribbon guides 26a, 26b, and 26c may easily slide along the print ribbon 18 as the print heads 12a, 12b, and 12c are moved back and forth across the recording medium.
To install the conventional multi-head printer ribbon cartridge 16, a user first mounts the housing 16 on the print head carriage. The exposed print section of the print ribbon 18 has some slack and thus lies loosely near the print heads 12a, 12b, and 12c. The user then separately mounts each of the ribbon guides 26a, 26b, and 26c onto respective printing heads 12a, 12b, and 12c. As illustrated in FIG. 3, this step requires the user to grasp each ribbon guide 26a and slide the ribbon guide 26a onto the print head 12a. As a final step, the user tightens the print ribbon 18 to remove any excess slack and to ensure that the print ribbon 18 is properly positioned over the printing elements of the print heads 12a, 12b, and 12c.
The conventional printer ribbon cartridge 16 has two major disadvantages. First, installation of the conventional printer ribbon cartridge is very cumbersome. Each of the ribbon guides 26a, 26b, and 26c slide and twist relative to, and independently of, the other ribbon guides. As a result, the user must individually mount each of the ribbon guides 26a, 26b, and 26c on the respective print heads 12a, 12b, and 12c. Second, installation is very messy. Because the user must handle each of the ribbon guides 26a, 26b, and 26c individually, the user's fingers are in close proximity with the print ribbon 18 as shown in FIG. 3. As a result, the user normally cannot avoid handling the messy and ink soaked print ribbon 18.
The present invention overcomes the cited disadvantages of the conventional printer ribbon cartridges. First, the present invention facilitates easy installation. The user may simultaneously mount all of the ribbon guides onto the respective print heads. Second, the present invention reduces the installation mess because the user handles only the ribbon guide carrier, rather than each individual ribbon guide.
These and other advantages of the present invention will become apparent upon reading and understanding the following detailed description of a preferred embodiment.